I've got a 4.6 motor and was on the ECR facebook site and noticed that they perform cooling mods to their pursuit motors. Since I already have an upgraded 4.6 I didn't feel it was fair to call them and ask what the mods were but I also thought it would be OK to ask the board. I did notice in August when I got my motor back that when it hit 100 in Austin my temp gauge would creep up but never to a dangerous spot. It cooled off here before I had time to debug. Subsequently I bought a Ron Davis radiator and sent my headers out to be silver ceramic coated. Can anyone speculate on what cooling mods ECR might be referring to for a 4.6? We are hitting 80 now and 100 is right around the corner.
Great question. When its 100 her in Denver my warmed over 4.6 temp will crreep up. It gets worse at higher altitudes, say 11,000ft. I have done many things, none of which made a big improvement.
Recored radiator with 3 core 'desert cooler' core.
Water wetter additives
Frexalite extream twin puller fans
Experimented with ignition timing.
Experimented with fuel/air mixture
Ceramic coated manifolds
Currently seriously considering larger area radiator with separate oil cooler. Even modifying front crossmember/bodywork to accept. I am pretty sure it needs a 20% oversize area radiator. Extra cores have a minor improvement since the air is already near engine temp by the time it gets to the exta core.
Cooling the 3.9 original motor was an issue in these conditions also - particularly at slow speed and high altitude.
Thats where I am at. I would love to hear any crazy ideas!
Great question. When its 100 her in Denver my warmed over 4.6 temp
Cooling the 3.9 original motor was an issue in these conditions also - particularly at slow speed and high altitude.
Thats where I am at. I would love to hear any crazy ideas!
I have been running my 3.9 D90 off road for 14yrs and have certainly experienced this i.e. when the outside temp is 90 (or higher), when the motor is working hard, especially in low range, it will get warm. I have a new OEM radiator and want to get a new water pump, both are important. That said, I want to try installing a different thermostat because there is one that is made for hot conditions. The downside, so I'm told, you get less heater output in the colder weather.
Having similar issues with a new 4.6. We fitted a new 3.5 radiator, and an external oil cooler- waiting to see if this does the trick. Also removed the huge Warn Power Plant winch fitted by PO.
Interesting topic and was always under the assumption factory cooling in good working condition should be a non issue. Getting ready to do a Turner 4.6 top hat block and was planning on just making sure all cooling components were also replaced. If anyone has specific knowledge on how to keep temps low I would also be interested.
Options would be Extra core in the radiator, thermostat as mentioned, good working viscous clutch and fan, ceramic coated headers, some say a mantec snorkel helps to keep temps lower, water wetter, etc and obviously keeping grill free of too many ancillaries.
Having the same issue with our 4.6, creeps up to 210 with a 180 stat if your moving slowly especially in low range. Larger capacity radiator makes sense but D2/P38's had the same radiator for 4.0 or 4.6....
Thats a great bit of info. Moving more air is a big part of the solution and the engine driven fan is very capable. Any improvement on it will have a positive effect on overheating. It just requires high revs to get the most out of it - which a more powerful fan would help.
bumping this old thread if there is any update since 2yrs ago.
The SF area got really hot this wkend, with ambient temp in 104 - 110F range.
During bumper to bumper traffic, without AC, my engine temp (via ODB2) showed 216F - i turned on the heater at full as precaution. Once I got on highway, cruising at 75-80mph, w/o AC, engine temp stayed at 206F.
Earlier in the day, took the truck off-road, <10mph, and temp gauge creeped up to around 225F (before red-zone on the factory temp gauge) and I turned heater on, pulled off, shut down and let it cool off.
So, now I'm thinking... if ambient temp is 104, engine temp reads 206 at 75-80mph, that could be because radiator is unable to keep up (cool). And that at low speed or sit idle, the factory fan isn't able to keep up.
Interestingly, today ambient temp was around a cool 95. I idled the truck at home after some city driving and IR'ed the top rad hose - it showed 190-ish, and lower rad hose was changing between 148 to 180. I could hear the fan get louder and quieter and louder and quiet - fluctuates. After about 15min of idling with hood open, the ODB2 temp reading creeped up to 212F. I'm thinking the fan clutch is going?
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